Lung collagen and elastin changes are implicated in functional alterations associated with aging as well as in lungs with and without airways obstruction. The relative insolubility of lung parenchymal collagens when compared with other soft tissue collagens may explain some of its functional capabilities as well as its biochemical characteristics. We will study the soluble collagen from the standpoint of initial cross-linking reactions and will investigate the effect of lathrogens on the formation of uncross-linked connective tissue proteins. We will utilize the same tissue for biochemical and mechanical studies in an effort to elucidate a possible contribution of one to the other. A long range goal of this project is to determine some of the biochemical changes which occur in lung connective tissue proteins which may contribute to loss of pulmonary function in aging and emphysematous states.